Retrospective Evaluation of Position of Mental Foramen and Its Relationship with Gonial Angle Using Cone Beam Computed Tomography

Introduction: Mental foramen (MF) appearance is quite diverse. Failure to properly diagnose and protect the nerve may result in its damage during medical procedures such as surgery and placement of dental implants. This study evaluated the position of MF and its relationship with gonial angle using cone beam computed tomography (CBCT) images. Methods: 128 gonial angles from 64 CBCT images were measured and divided into low-angle (≤125°) and high-angle (>125°) categories. MF was divided into five types considering its position in cross-sectional profiles: type A (under apex of first premolar); B (under apex of second premolar); C (between first and second premolars); D (anterior to first premolar); and E(posterior to second premolar).The length of mental canal and its buccolingual and superior-inferior position was also evaluated. Independent T-test and Chi-square tests were used with statistical significance set at P<0.05. Results: The highest frequency of MF position in the high and low-gonial angle categories was type C and the lowest in high-angle and low-angle were type E and D, respectively. The position of the foramen and measurements of the mental canal was not affected by age, gender, or gonial angle (P>0.05). Conclusion: Position of MF was not found to be related to patients’ age, sex, or gonial angles. Since a precise determination of the MF position is difficult due to its different anatomical variations and also because of potential damages during the treatment procedures in this area, radiographic analysis and determining its location among different populations is necessary.